Although I don't have a CT yet, I would imagine that a spring semester topic would be natural selection as it ties into genetics and reproduction. Once students understand how genes are passed on as well as concepts such as changes in expression due to environmental conditions, they will then be able to build upon these ideas and work on writing and building models to explain natural selection.
In the GSE's, the idea of artificial selection is listed as a topic under the broader category of natural selection. I think that using real-life examples of how humans have selected organisms with desirable traits and bred them over and over shows students a real life scenario that they can relate to, and how these processes have led to the world we live in now. This includes breeds of purebred dogs, modern corn plants, as well as plants that produce enormous amounts of flowers for the purpose of decoration. I like the idea of talking about dog breeds as many families own dogs and the health consequences of "pure-breeding" can be a great topic for debate.
In the GSE's, the idea of artificial selection is listed as a topic under the broader category of natural selection. I think that using real-life examples of how humans have selected organisms with desirable traits and bred them over and over shows students a real life scenario that they can relate to, and how these processes have led to the world we live in now. This includes breeds of purebred dogs, modern corn plants, as well as plants that produce enormous amounts of flowers for the purpose of decoration. I like the idea of talking about dog breeds as many families own dogs and the health consequences of "pure-breeding" can be a great topic for debate.